Re: vkernel migration

From:

Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>

Date:

Fri, 2 Feb 2007 22:15:22 -0800 (PST)

:> A great example is already in DragonFly - process checkpointing. I
:> don't even know how it works as well as it does.
:
:Has this been coupled with the new vkernel mods yet? In other words,
:could I build a checkpointable kernel and then pause it, put it away
:for a month, and come back to it? ( Pardon me if I'm sounding naive
:here. :) )
:------
:Dave Hayes - Consultant - Altadena CA, USA - dave@jetcafe.org
:>>> The opinions expressed above are entirely my own <<<
It won't work, but it would not be hard to save and restore the state:
* The checkpointing code doesn't understand VPAGETABLE
mappings. Offset and page directory settings would have to be
saved and restored.
* Network (TAP) interface code would have to reopen the interface and
re-set its parameters.
* Console driver would have to restore the console mode via termios.
* Kernel core would have to re-create the VM spaces for the various
processes on checkpoint restore (but otherwise would not have to do
anything fancy, since the VM spaces are controlled entirely by
VPAGETABLE mappings).
-Matt
Matthew Dillon
<dillon@backplane.com>